Nowadays, many vehicles are equipped with lighting modules including solid state lighting (SSL) elements such as LEDs. Such lighting elements are attractive because the lifetime of a SSL element such as a LED is such that replacement of the lighting element is unlikely to be necessary during the lifetime of the car. In addition, such elements may be used to provide a vehicle with a distinctive appearance, for instance by arranging the SSL elements in a particular shape such as a curved line around a main lighting module of the vehicle.
However, it is not straightforward to use SSL elements to generate functional lighting that must meet strict guidelines regarding beam shape for instance, because the directional nature of the luminous distribution produced by SSL elements is quite different to the luminous distribution produced by incandescent or halogen light bulbs. It is therefore not straightforward to produce lighting modules based on SSL elements in which certain functions such as for instance a daytime running light (DRL) or low beam are generated in a compliant manner. In addition, consumers appreciate such functional lighting functions to have a homogeneous appearance, such that the SSL elements and other optical elements, e.g. reflectors, implementing such light functions should not be visible.
An example of a vehicle lighting module is provided in U.S. Pat. No. 7,980,742 B2. The lighting module disclosed hereinhas an optical axis and comprises at least one LED, a reflector of the complex surface type, and a cylindrical lens with substantially vertical generatrices placed between the two foci of the arc of an ellipse. The at least one LED is disposed such that its light beam has a mean direction substantially orthogonal to the geometric axis of the reflector, which is situated relative to the plane of the rear face of the light emitting diode, on the emitted beam side. However, this arrangement does not obscure the optical components from an external view, and may be less suitable to generate certain beam types.